Improvement in communication quality in a wireless communication system is an important issue for wireless communication carriers to achieve a mobile telephone no matter where the telephone is.
One of the factors that affect the communication quality in a wireless communication system is varying radio quality with the position of a mobile station. Besides, the communication quality of a mobile station is affected by distance to the base station, blocker, radio-wave reflection, radio-wave interference, base station, transmission power, and others.
For the above, wireless communication carriers make attempts of improving communication quality through, for example, measuring communication quality with a radio-wave measuring car or by a person of a wireless communication carrier visiting the site in response to report from a user and determining an area that needs improvement in communication quality.
Concurrently, wireless communication carriers are proceeding installation of radio-waver amplifiers such as repeaters contributing to improvement in wireless communication quality. A radio-wave amplifier amplifies radio wave received from the base station and transmits the amplified radio wave to a blind areas such as underground space which radio wave has not conventionally reached. Installation of radio-wave amplifiers efficiently improves area quality at low costs.
In recent years, WiFi connection provided by a wireless LAN hot spot has gained attentions as one of the solutions to enlarge a cover area of an indoor or underground area. WiFi connection is capable of improving communication quality degraded mainly by a blocker. NTT Communications provides 4,000 hot spots serving as public WiFi over the country, and these hot spots are intensively arranged at points where lots of people gather, such as near stations.
Another solution to improve the radio quality is indoor/outdoor determination that determines whether a mobile station is located indoor or outdoor. The accuracy of the indoor/outdoor determination is enhanced by using map data based on positional information obtained from a mobile station, so that the mobile station is determined to be in an indoor or outdoor area.
In order to consider a radio-wave amplifier such as a repeater, the position of a radio-wave amplifier and a propagation loss and a propagation delay that are estimated are registered in a base station in advance. Using these pieces of information registered in the base station and the propagation loss value and the propagation delay that a mobile station measures, determination is made as to whether the mobile station is accommodated in the service area of the repeater.    [Patent Literature 1] Japanese Laid-open Patent Publication No. 2006-20043    [Patent Literature 2] Japanese National Publication of International Patent Application No. 2005-539409
A conventional method of determining an area communication quality of which is to be improved takes time and labor because a person of the communication carrier visits the site and measures the radio quality. Furthermore, this method is capable of determining an area having poor radio quality but is incapable of determining which path has poor radio quality in the determined area.
In determining the position of the radio-wave amplifier, the propagation loss value and the propagation delay of a mobile station are used. In the 3rd Generation Partnership Project (3GPP) standard, a message (MeasurementReport (TS 25.331)) receivable when the position of the mobile station is registered provide the propagation loss but not the propagation delay.
A radio-wave amplifier that the base station has not register may be installed inside a store. The base station does not recognize the installation parameters of such a radio-wave amplifier not being registered.
Indoor/outdoor determination using map data may be erroneously resulted because old map data not updated is used. Further, this determination has a difficulty in determining the detailed position of the mobile station, and the error in determination may not attain the correct result.